CN115479951A - Method and system for detecting surface defect type and shape of optical element - Google Patents
Method and system for detecting surface defect type and shape of optical element Download PDFInfo
- Publication number
- CN115479951A CN115479951A CN202211254039.7A CN202211254039A CN115479951A CN 115479951 A CN115479951 A CN 115479951A CN 202211254039 A CN202211254039 A CN 202211254039A CN 115479951 A CN115479951 A CN 115479951A
- Authority
- CN
- China
- Prior art keywords
- defect
- defects
- simulation
- light intensity
- light
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/01—Arrangements or apparatus for facilitating the optical investigation
- G01N2021/0106—General arrangement of respective parts
- G01N2021/0112—Apparatus in one mechanical, optical or electronic block
Landscapes
- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
Abstract
The invention relates to the technical field of damage detection of laser optical devices, in particular to a method and a system for detecting the type and the shape of surface defects of an optical element, which comprise the following steps: establishing a simulation model sample library, wherein the simulation model sample library comprises defect models in various shapes, electromagnetic field distribution near the defects and defect light intensity distribution; constructing an ultra-smooth surface defect detection system, and detecting the surface defects of the ultra-smooth element; and (4) reversely identifying the three-dimensional scale based on the electric field distribution characteristics. The invention can solve the problem that the three-dimensional dimensions such as depth and width of the defect can not be directly measured in the detection system, and the specific shape of the defect can be reversely obtained by obtaining the light intensity value through detection; firstly, simulating defects of various shapes to construct a simulation model library to obtain light field distribution near the defects of various shapes; specific scale values such as length, width, depth and the like of the defects can be obtained, the operation is simple and convenient, and the detection is efficient.
Description
Technical Field
The invention relates to the technical field of damage detection of laser optical devices, in particular to a method and a system for detecting the type and the shape of surface defects of an optical element.
Background
In recent years, ultra-smooth surface defects become important factors affecting laser damage thresholds, and it is important to detect defects and accurately guide machining in order to obtain a satisfactory ultra-smooth surface. The basis of defect-induced damage to an optically ultra-smooth surface is the modulation of the optical field by the defect. Although researchers at home and abroad carry out a great deal of research and study on defects, how to accurately judge the shape of the scratch and accurately position the three-dimensional scale information of the scratch is not studied in detail.
Laser is incident to the surface of a workpiece and interacts with the surface, and the polarization of emitted scattered light is changed, so that a detection system is set up for scratch detection, and the principle of the detection system utilizes ultra-smooth surface defects to modulate incident light so as to generate scattered light. Light enters the spectrometer through the optical fiber and the intensity change of the light field is monitored. At present, the sub-surface defect detection can only complete submicron-level two-dimensional information detection. However, the three-dimensional information of the defect cannot be directly and accurately measured, and the length, width and other information of the defect need to be quantitatively detected.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, and provides a method and a system for detecting the type and the shape of the surface defect of an optical element, which can quickly and accurately detect the three-dimensional scale information of the surface defect of the ultra-smooth optical element and accurately judge the shape of the defect.
The technical scheme adopted by the invention for solving the technical problems is as follows:
a system for detecting the type and shape of surface defects on an optical element, comprising:
step 1: establishing a simulation model sample library, wherein the simulation model sample library comprises defect models in various shapes, electromagnetic field distribution near the defects and defect light intensity distribution;
step 2: constructing an ultra-smooth surface defect detection system, and detecting the surface defects of the ultra-smooth element;
and step 3: and (4) reversely identifying the three-dimensional scale based on the electric field distribution characteristics.
Further, in step 1, the method for establishing the simulation model library comprises the following steps:
1-1, creating defect models in various shapes through FDTD simulation software;
1-2, simulating defects of various shapes by using simulation software FDTD to obtain electromagnetic field distribution;
1-3, obtaining the light field distribution characteristics near the defect based on simulation software FDTD;
1-4, establishing a characteristic model by utilizing the light field distribution characteristics, the maximum light intensity value, the light intensity change along with the depth and the like;
1-5, establishing a simulation model library through the characteristic model.
Further, in step 2, the method for building the ultra-smooth surface defect detection system comprises the following steps:
2-1, building a detection system;
2-2, performing ultra-smooth surface scattering imaging, and detecting the change of an optical field by using an optical fiber coupling spectrometer;
and 2-3, extracting field intensity distribution obtained by the spectrometer, extracting field intensity maximum values, light intensity distribution characteristics and the like.
Further, in step 3, the method for reversely identifying the three-dimensional scale of the electric field distribution characteristics comprises the following steps:
3-1, establishing the same type scratch evaluation function;
3-2, creating a search program and directly obtaining the field intensity distribution in the model library;
3-3, judging whether the light intensity of the simulated scratches is consistent with that of the actually measured scratches:
in practice, factors of laser irradiation size, system error and defect self error are considered, namely I F (x) And I R (x) Respectively the light intensity value, I, obtained by simulation and experimental measurement under the same scratch parameter F (x) And I R (x) Not exactly, a small amount e is set and the following decision is set:
|I F (x)-I R (x)|＜ε，
when | I F (x)-I R (x) If I satisfies the above formula, I is judged F (x) And I R (x) If the simulation defect model is relevant, extracting three-dimensional information of the corresponding simulation defect model, including depth, width, shape and the like, and taking the three-dimensional information as actual defect scale information; at this time, it is considered that the data relating to the simulated scratch matches the actual scratch data in the system test, and the data in the simulation model can be output as the actual scratch data. The epsilon value is determined by simulation and experiment to determine a range. If the formula is not satisfied, the previous step is returned.
Further, in the step 3-1, the scratch evaluation functions of the same type are established, and the scratch evaluation functions are as follows:
in an experiment, an optical path is built, so that incident light is scattered at a defect of a super-smooth surface, the optical fiber collects scattered light at the defect, and the collected scattered light is converged into a spectrometer by the optical fiber coupling spectrometer to obtain the intensity distribution of a light field;
extracting the characteristics of the light field distribution and extracting the maximum value of light intensity; comparing the light intensity distribution characteristics and the maximum light intensity values of the defects obtained by the experiment with the models in the simulation library, and when the models in the simulation library are basically consistent with the actually measured models, adopting the three-dimensional scale information of the simulation models as the scale information of the actual defects.
Further, the detection system for detecting the surface defect type and shape of the optical element for realizing the detection method comprises a laser, a spectroscope I, a convex lens I, a concave lens, a spectroscope II, a convex lens II, a laser super-smooth surface object, an optical fiber coupler, a spectrometer and a computer terminal which are sequentially arranged; the spectrometer is also connected with the frequency tube. Laser with a certain wavelength is incident to the laser, and is diffused and then converged, the beam splitter splits the light and finally converges the light to strike the surface of the object with the ultra-smooth surface, at the moment, the incident light at the defect position is scattered, and the scattered light is coupled into the spectrometer through the optical fiber coupler.
The method establishes a reasonable 3D simulation model of the surface defect, carries out simulation on the electromagnetic field distribution near the defect based on a time domain finite difference method, establishes an electromagnetic field distribution characteristic model library of different defect shapes according to different modulation effects of the defect on a high-power pulse laser field, reversely judges the shape and three-dimensional scale information of the defect by using the model library, combines a detection system, accurately positions the position and obtains corresponding information, and improves the detection efficiency and precision.
The invention has the technical effects that:
compared with the prior art, the invention can solve the problem that the three-dimensional dimensions such as the depth and the width of the defect can not be directly measured in a detection system, and in addition, the specific shape of the defect can be reversely obtained by obtaining the light intensity value through detection. The invention firstly simulates the defects of various shapes and constructs a simulation model library to obtain the light field distribution near the defects of various shapes. In actual detection, the maximum field intensity value of the defect position is detected through a spectrometer, three-dimensional scale information is obtained by matching in a simulation library, the specific scale values such as the length, the width and the depth of the defect can be obtained specifically, and the specific shape of the defect can be reversely obtained according to the light field distribution characteristics of the defect position. The method provided by the invention is matched with simulation to create a search program, and is simple and convenient to operate and efficient in detection.
Drawings
FIG. 1 is a flowchart of a method for detecting the type and shape of surface defects of an optical element according to the present invention;
FIG. 2 is an example model interface for simulation in accordance with the present invention;
FIG. 3 shows FDTD simulation of defect light field distribution characteristics of different shapes, where FIG. 3 (a) shows a rectangular defect and FIG. 3 (b) shows a triangular defect;
FIG. 4 is a graph of variation of scattered light intensity of rectangular defects with depth at different depths according to the present invention;
FIG. 5 is a graph showing the variation of the maximum intensity value of the triangular defect of the present invention at different widths;
FIG. 6 is a diagram of the optical path of the system for detecting the type and shape of the surface defect of the optical element according to the present invention.
In the figure, 1, a laser; 2. a beam splitter; 3. a convex lens; 4. a concave lens; 5. a beam splitter; 6. a convex lens; 7. an ultra-smooth surface article; 8. a fiber coupler; 9. a spectrometer; 10. a frequency tube; 11. a computer device.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the drawings of the specification.
Example 1:
as shown in fig. 1, the method and system for detecting the type and shape of the surface defect of the optical element according to the present embodiment includes:
step 1: establishing a simulation model sample library, wherein the simulation model sample library comprises defect models in various shapes, electromagnetic field distribution near the defects and defect light intensity distribution, and specifically comprises the following steps:
1-1, creating defect models in various shapes through FDTD simulation software;
1-2, simulating defects of various shapes by using simulation software FDTD to obtain electromagnetic field distribution;
1-3, obtaining light field distribution characteristics near the defect based on simulation software FDTD;
1-4, establishing a characteristic model by utilizing the light field distribution characteristics, the maximum light intensity value, the light intensity change along with the depth and the like;
1-5, establishing a simulation model library through the characteristic model.
Step 2: constructing an ultra-smooth surface defect detection system, and detecting the surface defects of the ultra-smooth element; the method specifically comprises the following steps:
2-1, building a detection system;
2-2, performing ultra-smooth surface scattering imaging, and detecting the change of an optical field by using an optical fiber coupling spectrometer;
and 2-3, extracting field intensity distribution obtained by the spectrometer, extracting the maximum value of the field intensity, the light intensity distribution characteristics and the like.
And step 3: reversely identifying the three-dimensional scale based on the electric field distribution characteristics; the method specifically comprises the following steps:
3-1, establishing the same type scratch evaluation function;
in the experiment, an optical path is built, so that incident light is scattered at a super-smooth surface defect, the optical fiber collects scattered light at the defect, and the collected scattered light is converged into a spectrometer by an optical fiber coupling spectrometer to obtain the intensity distribution of a light field; extracting the characteristics of the light field distribution and extracting the maximum value of light intensity; the defect part is obtained through experimentsComparing the light intensity distribution characteristics and the maximum light intensity values with models in a simulation library to find similarities, verifying and comparing through a formula, and if I is satisfied F (x)-I R (x) If the formula is less than epsilon, the model in the simulation library is basically consistent with the actually measured model, namely the three-dimensional scale information of the simulation model can be used as the scale information of the actual defect;
3-2, creating a search program and directly obtaining the field intensity distribution in the model library;
3-3, judging whether the light intensity of the simulated scratch is consistent with that of the actually measured scratch:
in practice, factors of laser irradiation size, system error and defect self error are considered, namely I F (x) And I R (x) Respectively the light intensity value, I, obtained by simulation and experimental measurement under the same scratch parameter F (x) And I R (x) Not exactly, a small amount e is set and the following decision is set:
|I F (x)-I R (x)|＜ε，
when I F (x)-I R (x) If I satisfies the above formula, I is judged F (x) And I R (x) If the simulation defect model is relevant, extracting three-dimensional information of the corresponding simulation defect model, including depth, width, shape and the like, and taking the three-dimensional information as actual defect scale information; at this time, it is considered that the data relating to the simulated scratch matches the actual scratch data in the system test, and the data in the simulation model can be output as the actual scratch data. The epsilon value is determined by simulation and experiment to determine a range. If the formula is not satisfied, the previous step is returned.
The shape of the defect can be reversely judged, the system is set up for detection, the light field distribution characteristics are obtained, and then the database is used for searching, and the shape of the corresponding scratch is judged. Firstly, an electromagnetic theory model is established through simulation by simulation software FDTD, and as shown in figure 2, three-dimensional scale information such as simulation depth and the like is carried out by a computer through establishing a corresponding defect model, and light field distribution characteristics near the defect are simulated.
As shown in fig. 6, it is a light path diagram of a detection system for detecting the type and shape of surface defects of an optical element, and includes a laser 1, a first spectroscope 2, a first convex lens 3, a concave lens 4, a second spectroscope 5, a second convex lens 6, a laser ultra-smooth surface object 7, an optical fiber coupler 8, a spectrometer 9, and a computer terminal 11, which are sequentially arranged; the spectrometer 9 is also connected to a frequency tube 10. The laser 1 emits laser with a certain wavelength, the laser is diffused and then converged, the spectroscope is used for splitting light and finally converging the light to the surface of the ultra-smooth surface object 7, the incident light at the defect can be scattered, and the scattered light is coupled into the spectrometer 9 through the optical fiber coupler 8. Fig. 3 shows the light field distribution characteristics of the surface defects of two different shapes, the left side is the light field distribution diagram of the rectangular scratch, and the right side is the light field distribution diagram of the triangular scratch.
The method can be used for quantitatively detecting the depth and width information of the surface defect of the ultra-smooth element, and the detection precision is improved. Firstly, a model of the surface defect is established in simulation software FDTD according to the figure 2, the depth and the width of the defect are simulated by the established model, the scattering light intensity distribution of the defect on an image surface is obtained through simulation, and a light intensity value is extracted.
Fig. 4 shows the variation of the light intensity values of the simulation model at different depths, and it can be seen that the maximum light intensity value of the rectangular defect at different depths is constantly changed, and the maximum light intensity value is gradually increased along with the increase of the depth. Fig. 5 shows the maximum light intensity value variation of the simulation model under different widths, and it can be seen that the maximum light intensity value of the triangular defect under different widths constantly varies, and the maximum light intensity value also shows an enhanced trend along with the increase of the width, so that the depth or the width of the defect in a certain shape can be distinguished by using parameters such as the maximum light intensity value. The mode of reverse quantitative detection of the three-dimensional scale of the defect does not need complex detection modes such as equipment scanning or multi-dimensional reconstruction and the like, is convenient to operate, and greatly improves the detection efficiency and the accuracy.
The ultra-smooth surface defect model can realize reverse judgment of surface defect detection, the establishment of the database can improve the theoretical basis for judgment of defect shapes and judgment of scale information, the shapes can be judged, the sizes of the width, depth and the like of the defects can be obtained quantitatively, matching is carried out through experiments, reverse judgment of the defect scales is realized, and the detection efficiency is improved.
The above embodiments are only specific examples of the present invention, and the scope of the present invention includes but is not limited to the above embodiments, and any suitable changes or modifications by those of ordinary skill in the art which are consistent with the claims of the present invention should fall within the scope of the present invention.
Claims (6)
1. A method for detecting the type and shape of surface defects of an optical element is characterized in that: the method comprises the following steps:
step 1: establishing a simulation model sample library, wherein the simulation model sample library comprises defect models in various shapes, electromagnetic field distribution near the defects and defect light intensity distribution;
step 2: constructing an ultra-smooth surface defect detection system, and detecting the surface defects of the ultra-smooth element;
and step 3: and reversely identifying the three-dimensional scale based on the electric field distribution characteristics.
2. The method as claimed in claim 1, wherein the defect type and shape of the optical element are detected by a method comprising the steps of: in step 1, the method for establishing the simulation model library comprises the following steps:
1-1, creating defect models in various shapes through FDTD simulation software;
1-2, simulating defects of various shapes by using simulation software FDTD to obtain electromagnetic field distribution;
1-3, obtaining the light field distribution characteristics near the defect based on simulation software FDTD;
1-4, establishing a characteristic model by utilizing the light field distribution characteristics, the maximum light intensity value and the light intensity variation with the depth;
1-5, establishing a simulation model library through the characteristic model.
3. The method as claimed in claim 1, wherein the defect type and shape of the optical element are detected by a method comprising the steps of: in step 2, the method for building the ultra-smooth surface defect detection system comprises the following steps:
2-1, building a detection system;
2-2, performing ultra-smooth surface scattering imaging, and detecting the change of an optical field by using an optical fiber coupling spectrometer;
and 2-3, extracting field intensity distribution obtained by the spectrometer, and extracting the characteristics of the maximum value of the field intensity and light intensity distribution.
4. The method of claim 1, wherein the method further comprises: in step 3, the method for reversely identifying the three-dimensional scale of the electric field distribution characteristics comprises the following steps: 3-1, establishing the same type scratch evaluation function;
3-2, establishing a search program and directly obtaining the field intensity distribution in the model library;
and 3-3, judging whether the light intensity of the simulated scratches is consistent with that of the actually measured scratches.
5. The method as claimed in claim 4, wherein the method further comprises the steps of: in the step 3-1, the same type scratch evaluation function is established, specifically as follows:
in the experiment, an optical path is built, so that incident light is scattered at a super-smooth surface defect, the optical fiber collects scattered light at the defect, and the collected scattered light is converged into a spectrometer by an optical fiber coupling spectrometer to obtain the intensity distribution of a light field;
extracting the characteristics of the light field distribution and extracting the maximum value of light intensity; comparing the light intensity distribution characteristics and the maximum light intensity values of the defects obtained by the experiment with the models in the simulation library, and when the models in the simulation library are basically consistent with the actually measured models, adopting the three-dimensional scale information of the simulation models as the scale information of the actual defects.
6. The method for detecting the type and shape of the surface defect of an optical element according to any one of claims 1 to 5, wherein: the detection system for detecting the surface defect type and shape of the optical element for realizing the detection method comprises a laser, a spectroscope I, a convex lens I, a concave lens, a spectroscope II, a convex lens II, a laser super-smooth surface object, an optical fiber coupler, a spectrometer and a computer terminal which are sequentially arranged; the spectrometer is also connected with the frequency tube.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211254039.7A CN115479951A (en) | 2022-10-13 | 2022-10-13 | Method and system for detecting surface defect type and shape of optical element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211254039.7A CN115479951A (en) | 2022-10-13 | 2022-10-13 | Method and system for detecting surface defect type and shape of optical element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115479951A true CN115479951A (en) | 2022-12-16 |
Family
ID=84395658
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211254039.7A Pending CN115479951A (en) | 2022-10-13 | 2022-10-13 | Method and system for detecting surface defect type and shape of optical element |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115479951A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117232790A (en) * | 2023-11-07 | 2023-12-15 | 中国科学院长春光学精密机械与物理研究所 | Method and system for evaluating surface defects of optical element based on two-dimensional scattering |
-
2022
- 2022-10-13 CN CN202211254039.7A patent/CN115479951A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117232790A (en) * | 2023-11-07 | 2023-12-15 | 中国科学院长春光学精密机械与物理研究所 | Method and system for evaluating surface defects of optical element based on two-dimensional scattering |
| CN117232790B (en) * | 2023-11-07 | 2024-02-02 | 中国科学院长春光学精密机械与物理研究所 | Method and system for evaluating surface defects of optical element based on two-dimensional scattering |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109916909B (en) | Method and device for detecting surface morphology and subsurface defect information of optical element | |
| CN104833679B (en) | A kind of microdefect three dimension scale is inversely demarcated and detection method | |
| CN103616165B (en) | Loss measurement of optic fibre system | |
| CN103543125B (en) | All-optical gas detection method and device based on Michelson interference principle | |
| CN103175837B (en) | Method and device for detecting defect in matrix | |
| CN102661855A (en) | Method and system for progressive additional lens detection based on optical coherence tomography | |
| CN115479951A (en) | Method and system for detecting surface defect type and shape of optical element | |
| CN105092585A (en) | Subsurface measuring device and method based on total internal reflection and optical coherence tomography | |
| KR101368930B1 (en) | Optical metrology using a support vector machine with simulated diffraction signal inputs | |
| CN106959206A (en) | Fused quartz element zero probability damage threshold Forecasting Methodology based on photo-thermal weak absorbing | |
| CN106289726A (en) | A kind of photon band-gap optical fiber backscattering distributed measurement method and device | |
| CN108592829A (en) | A kind of measuring device and method of non-cpntact measurement deep hole inside surface roughness | |
| CN202049112U (en) | Pearl quality detecting device | |
| CN107153050B (en) | A kind of device and method of index matching | |
| TWI805876B (en) | Loosely coupled inspection and metrology system for high-volume production process monitoring | |
| CN109407365B (en) | Device and method for measuring diffraction efficiency of liquid crystal grating device under laser action | |
| CN105277131A (en) | Measurement device and measurement method of three-dimensional pore structure | |
| CN109425409B (en) | A kind of photoelectric liquid-levle measuring device and method | |
| CN104062299A (en) | Device and method using amplified spontaneous emission(ASE) light source to test optical element damage threshold | |
| CN207516312U (en) | The Laser-Ultrasonic Nondestructive Testing System of laser injection fibre and coherent detection | |
| Tosi et al. | Performance analysis of a noncontact plastic fiber optical fiber displacement sensor with compensation of target reflectivity | |
| Zapata-Valencia et al. | Automatic method to measure the numerical aperture of a propagating Gaussian light beam. | |
| CN104792732A (en) | Refractometer for self-reference of light source distribution | |
| CN205581024U (en) | Optical element surface defect detecting device of transmission type synthetic aperture digital holographic art | |
| WO2020158033A1 (en) | Optical pulse testing device and optical pulse testing method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |